linux-kernel - Re: [bug report] dm: 'tried to init an initialized object' error triggered during device creation

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Message-ID: <09e676c5-8407-a0a6-313c-22fcfee4e488@huaweicloud.com>
Date: Thu, 31 Jul 2025 09:49:27 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Hou Tao <houtao@...weicloud.com>, Li Lingfeng <lilingfeng3@...wei.com>,
 agk@...hat.com, Mike Snitzer <snitzer@...nel.org>,
 Mikulas Patocka <mpatocka@...hat.com>, dm-devel@...ts.linux.dev,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 linux-block@...r.kernel.org
Cc: zhengqixing@...wei.com, yangerkun <yangerkun@...wei.com>,
 "zhangyi (F)" <yi.zhang@...wei.com>,
 "chengzhihao1@...wei.com" <chengzhihao1@...wei.com>,
 Li Lingfeng <lilingfeng@...weicloud.com>, "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [bug report] dm: 'tried to init an initialized object' error
 triggered during device creation

Hi,

在 2025/07/31 9:28, Hou Tao 写道:
> cc +linux-block
> 
> The disk->queue_kobj is initialized in add_disk() and is uninitialized
> in del_disk(). And it seems that blk_unregister_queue() in del_disk()
> doesn't uninitialize the queue_kobj completely, because it doesn't
> expect the queue_kobj will be added again. I think the right place to
> fix the problem is blk_unregister_queue(). How about just memset the
> queue_kobj as zero after deleting the queue_kobj in blk_unregister_queue() ?

I think it's better to move kobject_init to allocate disk:

1) alloc disk, kobject_init
2) register q, kobject_add
3) unregister q, kobject_del
4) free disk, kobject_put

With this, it's safe to add the kobject again.

Thanks,
Kuai